Figures supplied by the Dublin hospital show 636 children on waiting lists as of September, including 367 on the in-patient waiting list and 269 on the day case waiting list.
Two years ago, there were 536 children on the waiting list.
The figures have risen despite the Blackrock Clinic increasing the amount of deformity surgery it carries out for Crumlin on agreement with the HSE.
Consultant orthopaedic surgeon at Crumlin Pat Kiely said “there was a push to get an extra 40 children operated on this year, outside of Crumlin”.
Mr Kiely said Crumlin did not have enough staff to carry out all the surgery itself, but that there was “a visible anxiousness to improve the situation at ministerial and HSE level”, and the arrangement with the Blackrock Clinic had been agreed about a year ago.
Meanwhile, Crumlin is building a new orthopaedic theatre which Mr Kiely said was “the most fast-tracked project I have even seen”.
“It’s expected to be up and running next February, which is a startling achievement.”
Mr Kiely said they were relieved that there was a “real focus on making it happen and that we don’t have to wait for a new hospital”.
However, he said the concern was how the expanded theatre service would be structured, that they would need more beds and staff for the new theatre “otherwise, there was no point in hiring more surgeons”.
The consultant said they tried to work within HSE targets when carrying out surgery but that they “didn’t always get the theatre time”.
Mr Kiely founded a charity in 2011 called Straight Ahead to try and take children off the waiting list of whom the majority are in need of urgent spinal surgery for scoliosis, which causes significant curvature of the spine.
Delays in surgery can increase deformity in growing children and necessitate more complex and expensive surgeries.
Delays in other areas of paediatric orthopaedic surgery such as hip, knee, foot, and ankle surgery also lead to increased case complexity, scale, and costs of treatment and have a significant impact on children in terms of chronic pain and mobility.
The charity, which also involves colleagues of Mr Kiely’s at Crumlin, has carried out in excess of 60 surgeries to date on a pro-bono basis, including at South Infirmary Victoria University Hospital in Cork.
Mr Kiely said they were “looking at collaborating wherever we can” in carrying out surgeries which he said they could do for “50% less cost than the HSE”.
He said Straight Ahead was “able to work on the margins a bit more” because surgeons worked for free and medical companies donated devices or they were able to get discounts.
Meanwhile, Crumlin, in a statement, said it has received additional funding this year in the HSE service plan to prioritise spinal surgery.
“The HSE has also funded a capital build for a new orthopaedic theatre which is due to be handed over in the first quarter of 2016, and additional funding has also been submitted to the HSE for 2016,” the statement said.